1. Field of the Invention
The present invention generally relates to an image-forming device, a recording medium, and an image-forming device controlling method, and more particularly, to an image-forming device, such as a printer incorporating a heat-fixing device, and a multifunctional copying machine, to a recording medium, and to an image-forming device controlling method.
2. Description of the Related Art
Conventionally, in a well-known electrophotographic recording device (an image-forming device), such as a printer or a copying machine, which performs a printing by a heat-fixing method, a toner image formed on a photosensitive member is transferred to a recording paper by using an electrostatic power, and thereafter the recording paper bearing the toner image is conveyed to a heat-fixing device. In this heat-fixing device, while the recording paper is supported and conveyed by a fixing roller and a pressuring roller, a predetermined fixing heat is applied to the toner image on the recording paper under pressure imposed by nip portions of the fixing roller and the pressuring roller so as to fix the toner image on the recording paper. Such a heat-fixing device generally incorporates a heater generating a Joule heat in the fixing roller.
Since the temperature in the device may be excessively elevated due to the heat generated from the heater, the electrophotographic recording device further comprises a cooling fan revolving so as to prevent the temperature rise in the device.
However, the cooling fan is often laid out in the vicinity of the heat-fixing device; therefore, when the recording paper (especially the leading end thereof) enters the heat-fixing device, toner particles transferred to the recording paper flow around due to an air current generated by the cooling fan such that blurred images are likely and creases may be created in the recording paper. This effect is prominent especially when the recording paper is thinner than a predetermined thickness.
Thereupon, there has been proposed an image-forming device that reduces a revolving velocity (revolutions per unit time) of the cooling fan lower than normal throughout a conveyance path, and mechanically adjusts an amount of airflow, according to a type of a recording paper (Japanese Laid-Open Patent Application No. 07-319370).
Besides, FIG. 1 shows a relation between a surface temperature of a fixing roller and an elapse time from the start of the fixing roller being revolved in a conventional heat-fixing device (a fixing unit). In FIG. 1, the axis of ordinates indicates the surface temperature of the fixing roller. TFL plotted on this ordinate axis indicates the lower limit of the fixing temperature. TFH indicates the upper limit of the fixing temperature. TW indicates a target value of the standby temperature. In FIG. 1, the surface temperature increases from the standby temperature TW to the upper limit TFH, and then decreases due to an effect of the cooling fan. Thereafter, the surface temperature is maintained at a temperature TFO above the lower limit TFL, while also being prevented from increasing excessively.
The technology disclosed in Japanese Laid-Open Patent Application No. 07-319370 can prevent the occurrence of the above-mentioned blurred images or creases by reducing the revolving velocity of the cooling fan lower than normal, especially when printing on a thin recording paper. However, an image-forming device is required not only to prevent ill influences due to an air current generated by revolutions of the cooling fan, but also to restrict a temperature increase in the device.
It is a general object of the present invention to provide an improved and useful image-forming device, a recording medium, and an image-forming device controlling method in which the above-mentioned problems are eliminated.
A more specific object of the present invention is to provide an image-forming device, a recording medium, and an image-forming device controlling method which can not only prevent a transfer paper from being influenced by an air current generated by revolutions of a cooling fan, but also can sufficiently restrict a temperature increase in the image-forming device by revolving the cooling fan.
In order to achieve the above-mentioned objects, there is provided according to one aspect of the present invention an image-forming device comprising:
fixing means for fixing a toner visible image transferred to a transfer sheet;
feeding means for feeding and conveying the transfer sheet to the fixing means;
a cooling fan discharging a heat generated in the fixing means;
conveyance-position detecting means for detecting a conveyance position of the transfer sheet being conveyed; and
controlling means for controlling the cooling fan to start and stop revolving according to the conveyance position.
Normally, a cooling fan is used to prevent the temperature rise in an image-forming device. However, when a transfer sheet (especially the leading end thereof) enters a fixing device, toner particles transferred to the transfer sheet flow around due to an air current generated by the cooling fan such that blurred images are likely to be produced and creases may be created in the transfer sheet. Thereupon, by controlling the start/stop of the cooling fan according to the above-mentioned conveyance position, the air current generated by the cooling fan is prevented from affecting the transfer sheet after a transferring process until the completion of a fixing process. This makes it possible to eliminate the above-mentioned inconveniences of blurred images or creases in the transfer sheet, while keeping the reduction of cooling effects as little as possible.
In order to achieve the above-mentioned objects, there is also provided according to another aspect of the present invention an image-forming device comprising:
fixing means for fixing a toner visible image transferred to a transfer sheet;
feeding means for feeding and conveying the transfer sheet to the fixing means;
a cooling fan discharging a heat generated in the fixing means by revolving at a variable revolving velocity;
conveyance-position detecting means for detecting a conveyance position of the transfer sheet being conveyed; and
controlling means for controlling the revolving velocity of the cooling fan according to the conveyance position.
When the revolving velocity (revolutions per unit time) of the cooling fan is variable, the revolving velocity of the cooling fan is controlled according to positions of the transfer sheet being conveyed. This makes it possible to prevent the reduction of cooling effects much further than when the start/stop of the cooling fan is controlled.
In order to achieve the above-mentioned objects, there is also provided according to another aspect of the present invention an image-forming device comprising:
fixing means for fixing a toner visible image transferred to a transfer sheet;
feeding means for feeding and conveying the transfer sheet to the fixing means;
a cooling fan discharging a heat generated in the fixing means;
timing means for measuring a conveying time of the transfer sheet being conveyed; and
controlling means for calculating a conveyance position of the transfer sheet being conveyed, based on the conveying time and a predetermined conveying velocity, so as to control the cooling fan to start and stop revolving according to the conveyance position.
In cases where there are not provided conveyance sensors necessary for a cooling-fan control at sufficient positions on a conveyance path of the transfer sheet, a position of the transfer sheet being conveyed can be estimated by calculating a timing of the transfer sheet being conveyed, based on information detected by an existing conveyance sensor and a predetermined conveying velocity. Therefore, according to this estimation, the start/stop of the cooling fan can be controlled.
In order to achieve the above-mentioned objects, there is also provided according to another aspect of the present invention an image-forming device comprising:
fixing means for fixing a toner visible image transferred to a transfer sheet;
feeding means for feeding and conveying the transfer sheet to the fixing means;
a cooling fan discharging a heat generated in the fixing means by revolving at a variable revolving velocity;
timing means for measuring a conveying time of the transfer sheet being conveyed; and
controlling means for calculating a conveyance position of the transfer sheet being conveyed, based on the conveying time and a predetermined conveying velocity, so as to control the revolving velocity of the cooling fan according to the conveyance position.
In cases where there are not provided conveyance sensors necessary for a cooling-fan control at sufficient positions on a conveyance path of the transfer sheet, the conveyance position of the transfer sheet can be estimated by calculating a timing of the transfer sheet being conveyed, based on information detected by an existing conveyance sensor and a predetermined conveying velocity. Therefore, according to this estimation, the revolving velocity of the cooling fan can be controlled.
Additionally, in the image-forming device according to the present invention, the feeding means may continuously feed and convey a plurality of transfer sheets to the fixing means, and the controlling means may control the cooling fan to stop revolving when a preceding transfer sheet exists in a predetermined conveying range.
When a plurality of transfer sheets are being conveyed through the image-forming device, the transfer sheets are at different conveyance positions. Therefore, simply starting and stopping the cooling fan according to a position of a transfer sheet causes a confliction of processes with other transfer sheets being conveyed. Thereupon, when even one transfer sheet is being conveyed between the transferring device and the entrance of the fixing device, the start/stop of the cooling fan is exclusively controlled with respect to the transfer sheet. This eliminates the above-mentioned inconveniences even upon a continuous printing.
Additionally, in the image-forming device according to the present invention, the feeding means may continuously feed and convey a plurality of transfer sheets to the fixing means, and when a preceding transfer sheet exists in a predetermined conveying range, the controlling means may control the cooling fan to revolve at a revolving velocity lower than an initial revolving velocity upon the start of feeding the transfer sheets.
When a plurality of transfer sheets are being conveyed through the image-forming device, the transfer sheets are at different conveyance positions. Therefore, simply starting and stopping the cooling fan according to a position of a transfer sheet causes a confliction of processes with other transfer sheets being conveyed. Thereupon, when even one transfer sheet is being conveyed between the transferring device and the entrance of the fixing device, the revolving velocity of the cooling fan is exclusively controlled with respect to the transfer sheet. This eliminates the above-mentioned inconveniences even upon a continuous printing.
Additionally, in the image-forming device according to the present invention, the controlling means may control the cooling fan to stop revolving or to revolve at a revolving velocity lower than the initial revolving velocity at least while the transfer sheet is conveyed from transferring means to the fixing means, the transferring means transferring the toner visible image to the transfer sheet.
While a transfer sheet is conveyed from a transferring device (a transfer roller, a photosensitive member, etc.) to a fixing device, an air current generated by the cooling fan may likely flow toner particles on the transfer sheet. Thereupon, controlling the cooling fan to stop revolving or to revolve at a revolving velocity lower than the initial revolving velocity can eliminate the above-mentioned inconveniences of blurred images or creases in the transfer sheet, while keeping the reduction of cooling effects as little as possible.
Additionally, the image-forming device according to the present invention may further comprise temperature-sensing means for sensing a temperature in the image-forming device, wherein the controlling means may control the cooling fan to start revolving or to revolve at the initial revolving velocity when the temperature-sensing means senses a temperature equal to or higher than a predetermined temperature.
In this image-forming device, starting the revolution of the cooling fan or revolving the cooling fan at the above-mentioned initial revolving velocity according to the temperature in the image-forming device can prevent an abnormal increase in temperature so as to restrict the reduction of cooling effects.
Additionally, in the image-forming device according to the present invention, the controlling means may control the cooling fan to start revolving or to revolve at the initial revolving velocity when a predetermined time elapses since the cooling fan has stopped revolving or has been revolving at the revolving velocity lower than the initial revolving velocity.
It is not preferable to keep stopping the cooling fan or to keep reducing the revolving velocity of the cooling fan, because this may impair the cooling effects. Thereupon, when a predetermined time has elapsed, starting the cooling fan automatically or returning the revolving velocity of the cooling fan to the above-mentioned initial revolving velocity can maintain the cooling effects.
Additionally, the image-forming device according to the present invention may further comprise mode-setting means for setting a thin-sheet mode indicating that the transfer sheet is thinner than a predetermined thickness, wherein the controlling means may control the cooling fan to start and stop revolving, or may control the revolving velocity of the cooling fan, according to the conveyance position, in the thin-sheet mode.
When a transfer sheet is thinner than a predetermined thickness, toner particles transferred to the transfer sheet are more likely to flow around due to an air current generated by the cooling fan, before the transfer sheet enters the fixing device. Thereupon, only in the thin-sheet mode, the start/stop of the cooling fan or the revolving velocity thereof can be controlled according to a position of the transfer sheet being conveyed so as to eliminate the above-mentioned inconveniences of blurred images or creases in the thinner transfer sheet, while maintaining cooling effects of an ordinary cooling-fan control with respect to a normal transfer sheet as thick as or thicker than the predetermined thickness.
In order to achieve the above-mentioned objects, there is also provided according to another aspect of the present invention a computer readable recording medium storing program code for causing an image-forming device to control fixing means for fixing a toner visible image transferred to a transfer sheet, feeding means for feeding and conveying the transfer sheet to the fixing means, a cooling fan discharging a heat generated in the fixing means, and conveyance-position detecting means for detecting a conveyance position of the transfer sheet being conveyed, the recording medium comprising:
conveyance-position detecting program code means for detecting the conveyance position of the transfer sheet being conveyed; and
controlling program code means for controlling the cooling fan to start and stop revolving according to the conveyance position, or for controlling the revolving velocity of the cooling fan according to the conveyance position.
By providing the image-forming device with a recording medium storing programs for controlling the start/stop of the cooling fan, or for controlling the revolving velocity of the cooling fan, according to the above-mentioned conveyance position of a transfer sheet judged from information detected by a resist sensor, etc., a controller (or a CPU) of the image-forming device can easily obtain the above-mentioned programs. The controller executes the programs so as to eliminate the above-mentioned inconveniences of blurred images or creases in the transfer sheet while keeping the reduction of cooling effects as little as possible.
In order to achieve the above-mentioned objects, there is also provided according to another aspect of the present invention a computer readable recording medium storing program code for causing an image-forming device to control fixing means for fixing a toner visible image transferred to a transfer sheet, feeding means for feeding and conveying the transfer sheet to the fixing means, a cooling fan discharging a heat generated in the fixing means, and timing means for measuring a conveying time of the transfer sheet being conveyed, the recording medium comprising:
conveyance-position calculating program code means for calculating a conveyance position of the transfer sheet being conveyed, based on the conveying time and a predetermined conveying velocity; and
controlling program code means for controlling the cooling fan to start and stop revolving according to the conveyance position, or for controlling the revolving velocity of the cooling fan according to the conveyance position.
By providing the image-forming device with a recording medium storing programs for controlling the start/stop of the cooling fan, or for controlling the revolving velocity of the cooling fan, according to the above-mentioned conveyance position of a transfer sheet calculated from information detected by a resist sensor, the conveying time of the transfer sheet measured by the timing means, the predetermined conveying velocity, etc., a controller of the image-forming device can easily obtain the above-mentioned programs. The controller executes the programs so as to eliminate the above-mentioned inconveniences of blurred images or creases in the transfer sheet while keeping the reduction of cooling effects as little as possible.
In order to achieve the above-mentioned objects, there is also provided according to another aspect of the present invention a computer readable recording medium storing program code for causing an image-forming device to control transferring means for transferring a toner visible image to a transfer sheet, fixing means for fixing the toner visible image transferred to the transfer sheet, feeding means for feeding and conveying the transfer sheet to the fixing means, a cooling fan discharging a heat generated in the fixing means, and conveyance-position detecting means for detecting a conveyance position of the transfer sheet being conveyed, the recording medium comprising:
conveyance-position detecting program code means for detecting the conveyance position of the transfer sheet being conveyed; and
controlling program code means for controlling the cooling fan to stop revolving, or to revolve at a revolving velocity lower than an initial revolving velocity upon the start of feeding transfer sheets, when a transfer sheet preceding the present transfer sheet exists between the transferring means and the fixing means, while continuously feeding and conveying a plurality of transfer sheets to the fixing means.
The image-forming device can be provided with a recording medium storing programs for controlling the cooling fan to stop revolving, or to revolve at a revolving velocity lower than the above-mentioned initial revolving velocity, when a preceding transfer sheet exists between the transferring device and the fixing device, while controlling the start/stop of the cooling fan, or controlling the revolving velocity of the cooling fan, according to the above-mentioned conveyance position of a transfer sheet judged from information detected by a resist sensor, etc. In this arrangement, a controller of the image-forming device can easily obtain the above-mentioned programs. The controller executes the programs so as to eliminate the above-mentioned inconveniences of blurred images or creases in the transfer sheet while maintaining the cooling effects, even when continuously feeding and conveying a plurality of transfer sheets.
In order to achieve the above-mentioned objects, there is also provided according to another aspect of the present invention a computer readable recording medium storing program code for causing an image-forming device to control transferring means for transferring a toner visible image to a transfer sheet, fixing means for fixing the toner visible image transferred to the transfer sheet, feeding means for feeding and conveying the transfer sheet to the fixing means, a cooling fan discharging a heat generated in the fixing means, and timing means for measuring a conveying time of the transfer sheet being conveyed, the recording medium comprising:
conveyance-position calculating program code means for calculating a conveyance position of the transfer sheet being conveyed, based on the conveying time and a predetermined conveying velocity; and
controlling program code means for controlling the cooling fan to stop revolving, or to revolve at a revolving velocity lower than an initial revolving velocity upon the start of feeding transfer sheets, when a transfer sheet preceding the present transfer sheet exists between the transferring means and the fixing means, while continuously feeding and conveying a plurality of transfer sheets to the fixing means.
The image-forming device can be provided with a recording medium storing programs for controlling the cooling fan to stop revolving, or to revolve at a revolving velocity lower than the above-mentioned initial revolving velocity, when a preceding transfer sheet exists between the transferring device and the fixing device, while controlling the start/stop or the revolving velocity of the cooling fan according to the above-mentioned conveyance position of a transfer sheet calculated from information detected by a resist sensor, the conveying time of the transfer sheet measured by the timing means, the predetermined conveying velocity, etc. In this arrangement, a controller of the image-forming device can easily obtain the above-mentioned programs. The controller executes the programs so as to eliminate the above-mentioned inconveniences of blurred images or creases in the transfer sheet while maintaining the cooling effects, even when continuously feeding and conveying a plurality of transfer sheets.
In order to achieve the above-mentioned objects, there is also provided according to another aspect of the present invention a computer readable recording medium storing program code for causing an image-forming device to control transferring means for transferring a toner visible image to a transfer sheet, fixing means for fixing the toner visible image transferred to the transfer sheet, feeding means for feeding and conveying the transfer sheet to the fixing means, a cooling fan discharging a heat generated in the fixing means, conveyance-position detecting means for detecting a conveyance position of the transfer sheet being conveyed, and temperature-sensing means for sensing a temperature in the image-forming device, the recording medium comprising:
conveyance-position detecting program code means for detecting the conveyance position of the transfer sheet being conveyed;
first controlling program code means for controlling the cooling fan to stop revolving or to revolve at a revolving velocity lower than an initial revolving velocity upon the start of feeding transfer sheets when a transfer sheet preceding the present transfer sheet exists between the transferring means and the fixing means while continuously feeding and conveying a plurality of transfer sheets to the fixing means; and
second controlling program code means for controlling the cooling fan to start revolving or to revolve at the initial revolving velocity when the temperature in the image-forming device becomes equal to or higher than a predetermined temperature since the cooling fan is stopped revolving or is revolved at the revolving velocity lower than the initial revolving velocity by the first controlling program code means.
The image-forming device can be provided with a recording medium storing programs for not only controlling the cooling fan to stop revolving, or to revolve at a revolving velocity lower than the above-mentioned initial revolving velocity, when a preceding transfer sheet exists between the transferring device and the fixing device, but also controlling the cooling fan to start revolving or to revolve at the initial revolving velocity when the temperature in the image-forming device becomes equal to or higher than a predetermined temperature, while controlling the start/stop or the revolving velocity of the cooling fan according to the above-mentioned conveyance position of a transfer sheet judged from information detected by a resist sensor, etc. In this arrangement, a controller of the image-forming device can easily obtain the above-mentioned programs. The controller executes the programs so as to eliminate the above-mentioned inconveniences of blurred images or creases in the transfer sheet while maintaining sufficient cooling effects, even when continuously feeding and conveying a plurality of transfer sheets.
In order to achieve the above-mentioned objects, there is also provided according to another aspect of the present invention a computer readable recording medium storing program code for causing an image-forming device to control transferring means for transferring a toner visible image to a transfer sheet, fixing means for fixing the toner visible image transferred to the transfer sheet, feeding means for feeding and conveying the transfer sheet to the fixing means, a cooling fan discharging a heat generated in the fixing means, and timing means for measuring a conveying time of the transfer sheet being conveyed, the recording medium comprising:
conveyance-position calculating program code means for calculating a conveyance position of the transfer sheet being conveyed, based on the conveying time and a predetermined conveying velocity;
first controlling program code means for controlling the cooling fan to stop revolving or to revolve at a revolving velocity lower than an initial revolving velocity upon the start of feeding transfer sheets, when a transfer sheet preceding the present transfer sheet exists between the transferring means and the fixing means, while continuously feeding and conveying a plurality of transfer sheets to the fixing means; and
second controlling program code means for controlling the cooling fan to start revolving or to revolve at the initial revolving velocity when a predetermined time elapses since the cooling fan is stopped revolving or is revolved at the revolving velocity lower than the initial revolving velocity by the first controlling program code means.
The image-forming device can be provided with a recording medium storing programs for not only controlling the cooling fan to stop revolving, or to revolve at a revolving velocity lower than the above-mentioned initial revolving velocity, when a preceding transfer sheet exists between the transferring device and the fixing device, but also controlling the cooling fan to start revolving or to revolve at the initial revolving velocity when a predetermined time elapses since the cooling fan has been stopped revolving or revolved at the revolving velocity lower than the initial revolving velocity, while controlling the start/stop or the revolving velocity of the cooling fan according to the above-mentioned conveyance position of a transfer sheet calculated from information detected by a resist sensor, the conveying time of the transfer sheet measured by the timing means, the predetermined conveying velocity, etc. In this arrangement, a controller of the image-forming device can easily obtain the above-mentioned programs. The controller executes the programs so as to eliminate the above-mentioned inconveniences of blurred images or creases in the transfer sheet while maintaining the cooling effects, even when continuously feeding and conveying a plurality of transfer sheets.
Additionally, in the recording medium according to the present invention, the image-forming device may include mode-setting means for setting a thin-sheet mode indicating that the transfer sheet is thinner than a predetermined thickness, and the recording medium may further comprise:
mode confirming program code means for confirming whether or not the thin-sheet mode is set so that each of the above-mentioned program code means is performed only when the thin-sheet mode is set.
Especially when a transfer sheet is thinner than a predetermined thickness, toner particles transferred to the transfer sheet are more likely to flow around due to an air current generated by the cooling fan, before the transfer sheet enters the fixing device. Thereupon, the image-forming device can be provided with a recording medium storing programs for performing the above-mentioned thin-sheet mode. In this arrangement, a controller of the image-forming device can easily obtain the above-mentioned programs. The controller executes the programs so as to eliminate the above-mentioned inconveniences of blurred images or creases in the transfer sheet while maintaining sufficient cooling effects.
In order to achieve the above-mentioned objects, there is also provided according to another aspect of the present invention a method for controlling an image-forming device including fixing means for fixing a toner visible image transferred to a transfer sheet, feeding means for feeding and conveying the transfer sheet to the fixing means, a cooling fan discharging a heat generated in the fixing means, and conveyance-position detecting means for detecting a conveyance position of the transfer sheet being conveyed, the method comprising:
the conveyance-position detecting step of detecting the conveyance position of the transfer sheet being conveyed; and
the controlling step of controlling the cooling fan to start and stop revolving according to the conveyance position, or controlling the revolving velocity of the cooling fan according to the conveyance position.
The image-forming device can read programs from a network in a file format or from a recording medium, the programs for performing the method of controlling the start/stop of the cooling fan, or of controlling the revolving velocity of the cooling fan, according to the above-mentioned conveyance position of a transfer sheet judged from information detected by a resist sensor, etc. A controller of the image-forming device executes the programs for performing the method so as to eliminate the above-mentioned inconveniences of blurred images or creases in the transfer sheet while maintaining sufficient cooling effects.
In order to achieve the above-mentioned objects, there is also provided according to another aspect of the present invention a method for controlling an image-forming device including fixing means for fixing a toner visible image transferred to a transfer sheet, feeding means for feeding and conveying the transfer sheet to the fixing means, a cooling fan discharging a heat generated in the fixing means, and timing means for measuring a conveying time of the transfer sheet being conveyed, the method comprising:
the conveyance-position calculating step of calculating a conveyance position of the transfer sheet being conveyed, based on the conveying time and a predetermined conveying velocity; and
the controlling step of controlling the cooling fan to start and stop revolving according to the conveyance position, or controlling the revolving velocity of the cooling fan according to the conveyance position.
The image-forming device can read programs from a network in a file format or from a recording medium, the programs for performing the method of controlling the start/stop or the revolving velocity of the cooling fan according to the above-mentioned conveyance position of a transfer sheet calculated from information detected by a resist sensor, the conveying time of the transfer sheet measured by the timing means, the predetermined conveying velocity, etc. A controller of the image-forming device executes the programs for performing the method so as to eliminate the above-mentioned inconveniences of blurred images or creases in the transfer sheet while maintaining sufficient cooling effects.
In order to achieve the above-mentioned objects, there is also provided according to another aspect of the present invention a method for controlling an image-forming device including transferring means for transferring a toner visible image to a transfer sheet, fixing means for fixing the toner visible image transferred to the transfer sheet, feeding means for feeding and conveying the transfer sheet to the fixing means, a cooling fan discharging a heat generated in the fixing means, and conveyance-position detecting means for detecting a conveyance position of the transfer sheet being conveyed, the method comprising:
the conveyance-position detecting step of detecting the conveyance position of the transfer sheet being conveyed; and
the controlling step of controlling the cooling fan to stop revolving or to revolve at a revolving velocity lower than an initial revolving velocity upon the start of feeding transfer sheets, when a transfer sheet preceding the present transfer sheet exists between the transferring means and the fixing means, while continuously feeding and conveying a plurality of transfer sheets to the fixing means.
The image-forming device can read programs from a network in a file format or from a recording medium, the programs for performing the method of controlling the cooling fan to stop revolving, or to revolve at a revolving velocity lower than the above-mentioned initial revolving velocity, when a preceding transfer sheet exists between the transferring device and the fixing device, while controlling the start/stop or the revolving velocity of the cooling fan according to the above-mentioned conveyance position of a transfer sheet judged from information detected by a resist sensor, etc. A controller of the image-forming device executes the programs for performing the method so as to eliminate the above-mentioned inconveniences of blurred images or creases in the transfer sheet while maintaining sufficient cooling effects, even when continuously feeding and conveying a plurality of transfer sheets.
In order to achieve the above-mentioned objects, there is also provided according to another aspect of the present invention a method for controlling an image-forming device including transferring means for transferring a toner visible image to a transfer sheet, fixing means for fixing the toner visible image transferred to the transfer sheet, feeding means for feeding and conveying the transfer sheet to the fixing means, a cooling fan discharging a heat generated in the fixing means, and timing means for measuring a conveying time of the transfer sheet being conveyed, the method comprising:
the conveyance-position calculating step of calculating a conveyance position of the transfer sheet being conveyed, based on the conveying time and a predetermined conveying velocity; and
the controlling step of controlling the cooling fan to stop revolving or to revolve at a revolving velocity lower than an initial revolving velocity upon the start of feeding transfer sheets, when a transfer sheet preceding the present transfer sheet exists between the transferring means and the fixing means, while continuously feeding and conveying a plurality of transfer sheets to the fixing means.
The image-forming device can read programs from a network in a file format or from a recording medium, the programs for performing the method of controlling the cooling fan to stop revolving, or to revolve at a revolving velocity lower than the above-mentioned initial revolving velocity, when a preceding transfer sheet exists between the transferring device and the fixing device, while controlling the start/stop or the revolving velocity of the cooling fan according to the above-mentioned conveyance position of a transfer sheet calculated from information detected by a resist sensor, the conveying time of the transfer sheet measured by the timing means, the predetermined conveying velocity, etc. A controller of the image-forming device executes the programs for performing the method so as to eliminate the above-mentioned inconveniences of blurred images or creases in the transfer sheet while maintaining sufficient cooling effects, even when continuously feeding and conveying a plurality of transfer sheets.
In order to achieve the above-mentioned objects, there is also provided according to another aspect of the present invention a method for controlling an image-forming device including transferring means for transferring a toner visible image to a transfer sheet, fixing means for fixing the toner visible image transferred to the transfer sheet, feeding means for feeding and conveying the transfer sheet to the fixing means, a cooling fan discharging a heat generated in the fixing means, conveyance-position detecting means for detecting a conveyance position of the transfer sheet being conveyed, and temperature-sensing means for sensing a temperature in the image-forming device, the method comprising:
the conveyance-position detecting step of detecting the conveyance position of the transfer sheet being conveyed;
the first controlling step of controlling the cooling fan to stop revolving or to revolve at a revolving velocity lower than an initial revolving velocity upon the start of feeding transfer sheets, when a transfer sheet preceding the present transfer sheet exists between the transferring means and the fixing means, while continuously feeding and conveying a plurality of transfer sheets to the fixing means; and
the second controlling step of controlling the cooling fan to start revolving or to revolve at the initial revolving velocity, when the temperature in the image-forming device becomes equal to or higher than a predetermined temperature since the cooling fan is stopped revolving or is revolved at the revolving velocity lower than the initial revolving velocity by the first controlling step.
The image-forming device can read programs from a network in a file format or from a recording medium, the programs for performing the method of not only controlling the cooling fan to stop revolving or to revolve at a revolving velocity lower than the above-mentioned initial revolving velocity, when a preceding transfer sheet exists between the transferring device and the fixing device, but also controlling the cooling fan to start revolving or to revolve at the initial revolving velocity when the temperature in the image-forming device becomes equal to or higher than a predetermined temperature, while controlling the start/stop or the revolving velocity of the cooling fan according to the above-mentioned conveyance position of a transfer sheet judged from information detected by a resist sensor, etc. A controller of the image-forming device executes the programs for performing the method so as to eliminate the above-mentioned inconveniences of blurred images or creases in the transfer sheet while maintaining sufficient cooling effects, even when continuously feeding and conveying a plurality of transfer sheets.
In order to achieve the above-mentioned objects, there is also provided according to another aspect of the present invention a method for controlling an image-forming device including transferring means for transferring a toner visible image to a transfer sheet, fixing means for fixing the toner visible image transferred to the transfer sheet, feeding means for feeding and conveying the transfer sheet to the fixing means, a cooling fan discharging a heat generated in the fixing means, and timing means for measuring a conveying time of the transfer sheet being conveyed, the method comprising:
the conveyance-position calculating step of calculating a conveyance position of the transfer sheet being conveyed, based on the conveying time and a predetermined conveying velocity;
the first controlling step of controlling the cooling fan to stop revolving or to revolve at a revolving velocity lower than an initial revolving velocity upon the start of feeding transfer sheets, when a transfer sheet preceding the present transfer sheet exists between the transferring means and the fixing means, while continuously feeding and conveying a plurality of transfer sheets to the fixing means; and
the second controlling step of controlling the cooling fan to start revolving or to revolve at the initial revolving velocity, when a predetermined time elapses since the cooling fan is stopped revolving or is revolved at the revolving velocity lower than the initial revolving velocity by the first controlling step.
The image-forming device can read programs from a network in a file format or from a recording medium, the programs for performing the method of not only controlling the cooling fan to stop revolving or to revolve at a revolving velocity lower than the above-mentioned initial revolving velocity, when a preceding transfer sheet exists between the transferring device and the fixing device, but also controlling the cooling fan to start revolving or to revolve at the initial revolving velocity when a predetermined time elapses since the cooling fan has been stopped revolving or revolved at the revolving velocity lower than the initial revolving velocity, while controlling the start/stop or the revolving velocity of the cooling fan according to the above-mentioned conveyance position of a transfer sheet calculated from information detected by a resist sensor, the conveying time of the transfer sheet measured by the timing means, the predetermined conveying velocity, etc. A controller of the image-forming device executes the programs for performing the method so as to eliminate the above-mentioned inconveniences of blurred images or creases in the transfer sheet while maintaining sufficient cooling effects, even when continuously feeding and conveying a plurality of transfer sheets.
Additionally, in the image-forming device controlling method according to the present invention, the image-forming device may include mode-setting means for setting a thin-sheet mode indicating that the transfer sheet is thinner than a predetermined thickness, and the method may further comprise:
the mode confirming step of confirming whether or not the thin-sheet mode is set so that each of the above-mentioned steps is performed only when the thin-sheet mode is set.
Generally in an image-forming device, when a transfer sheet is thinner than a predetermined thickness, toner particles transferred to the transfer sheet are more likely to flow around due to an air current generated by the cooling fan, before the transfer sheet enters the fixing device. Thereupon, the image-forming device according to the present invention can read programs from a network in a file format or from a recording medium, the programs for performing the method of conducting the above-mentioned thin-sheet mode. A controller of the image-forming device executes the programs for performing the method so as to eliminate the above-mentioned inconveniences of blurred images or creases in the transfer sheet while maintaining sufficient cooling effects.
Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.